blob: c0be17e0ab82f4285921f63b7d178deeea07fa14 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/mach-pxa/dma.c
3 *
4 * PXA DMA registration and IRQ dispatching
5 *
6 * Author: Nicolas Pitre
7 * Created: Nov 15, 2001
8 * Copyright: MontaVista Software Inc.
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/interrupt.h>
19#include <linux/errno.h>
20
21#include <asm/system.h>
22#include <asm/irq.h>
Russell Kinga09e64f2008-08-05 16:14:15 +010023#include <mach/hardware.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <asm/dma.h>
25
Russell Kinga09e64f2008-08-05 16:14:15 +010026#include <mach/pxa-regs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Eric Miaof53f0662007-06-22 05:40:17 +010028struct dma_channel {
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 char *name;
Eric Miaof53f0662007-06-22 05:40:17 +010030 pxa_dma_prio prio;
Linus Torvalds0cd61b62006-10-06 10:53:39 -070031 void (*irq_handler)(int, void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 void *data;
Eric Miaof53f0662007-06-22 05:40:17 +010033};
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Eric Miaof53f0662007-06-22 05:40:17 +010035static struct dma_channel *dma_channels;
36static int num_dma_channels;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38int pxa_request_dma (char *name, pxa_dma_prio prio,
Linus Torvalds0cd61b62006-10-06 10:53:39 -070039 void (*irq_handler)(int, void *),
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 void *data)
41{
42 unsigned long flags;
43 int i, found = 0;
44
45 /* basic sanity checks */
46 if (!name || !irq_handler)
47 return -EINVAL;
48
49 local_irq_save(flags);
50
Nicolas Pitre99532552006-05-05 22:32:24 +010051 do {
52 /* try grabbing a DMA channel with the requested priority */
Eric Miaof53f0662007-06-22 05:40:17 +010053 for (i = 0; i < num_dma_channels; i++) {
54 if ((dma_channels[i].prio == prio) &&
55 !dma_channels[i].name) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 found = 1;
57 break;
58 }
59 }
Nicolas Pitre99532552006-05-05 22:32:24 +010060 /* if requested prio group is full, try a hier priority */
61 } while (!found && prio--);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 if (found) {
64 DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
65 dma_channels[i].name = name;
66 dma_channels[i].irq_handler = irq_handler;
67 dma_channels[i].data = data;
68 } else {
69 printk (KERN_WARNING "No more available DMA channels for %s\n", name);
70 i = -ENODEV;
71 }
72
73 local_irq_restore(flags);
74 return i;
75}
76
77void pxa_free_dma (int dma_ch)
78{
79 unsigned long flags;
80
81 if (!dma_channels[dma_ch].name) {
82 printk (KERN_CRIT
83 "%s: trying to free channel %d which is already freed\n",
Harvey Harrison8e86f422008-03-04 15:08:02 -080084 __func__, dma_ch);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 return;
86 }
87
88 local_irq_save(flags);
89 DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
90 dma_channels[dma_ch].name = NULL;
91 local_irq_restore(flags);
92}
93
Linus Torvalds0cd61b62006-10-06 10:53:39 -070094static irqreturn_t dma_irq_handler(int irq, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
96 int i, dint = DINT;
97
Eric Miaof53f0662007-06-22 05:40:17 +010098 for (i = 0; i < num_dma_channels; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 if (dint & (1 << i)) {
100 struct dma_channel *channel = &dma_channels[i];
101 if (channel->name && channel->irq_handler) {
Linus Torvalds0cd61b62006-10-06 10:53:39 -0700102 channel->irq_handler(i, channel->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 } else {
104 /*
105 * IRQ for an unregistered DMA channel:
106 * let's clear the interrupts and disable it.
107 */
108 printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
109 DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
110 }
111 }
112 }
113 return IRQ_HANDLED;
114}
115
Eric Miaof53f0662007-06-22 05:40:17 +0100116int __init pxa_init_dma(int num_ch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117{
Eric Miaof53f0662007-06-22 05:40:17 +0100118 int i, ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
Eric Miaof53f0662007-06-22 05:40:17 +0100120 dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
121 if (dma_channels == NULL)
122 return -ENOMEM;
123
124 ret = request_irq(IRQ_DMA, dma_irq_handler, IRQF_DISABLED, "DMA", NULL);
125 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
Eric Miaof53f0662007-06-22 05:40:17 +0100127 kfree(dma_channels);
128 return ret;
129 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Eric Miaof53f0662007-06-22 05:40:17 +0100131 /* dma channel priorities on pxa2xx processors:
132 * ch 0 - 3, 16 - 19 <--> (0) DMA_PRIO_HIGH
133 * ch 4 - 7, 20 - 23 <--> (1) DMA_PRIO_MEDIUM
134 * ch 8 - 15, 24 - 31 <--> (2) DMA_PRIO_LOW
135 */
136 for (i = 0; i < num_ch; i++)
137 dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
138
139 num_dma_channels = num_ch;
140 return 0;
141}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
143EXPORT_SYMBOL(pxa_request_dma);
144EXPORT_SYMBOL(pxa_free_dma);